1. Field of the Invention
The present invention relates to a furnace observation apparatus for observing the state of a high temperature atmosphere furnace such as a glass melting furnace or an incinerator.
2. Discussion of the Background
JP-A-9-307795 discloses a furnace observation apparatus comprising a cylindrical member to be inserted in a furnace and a CCD camera attached to the forward end of the cylindrical member, wherein the cylindrical member has a multi-cylinder structure comprising a plurality of cylinders, and it is constructed to photograph the state in the high temperature atmosphere furnace while cooling the CCD camera by supplying a cooling liquid or a cooling gas to a space between such cylinders.
However, such a conventional furnace observation apparatus has had a drawback that the structure of the apparatus tends to be complex, since the cylindrical member is constructed to have a multi cylinder structure to let the cylindrical member have a cooling function.
Further, such a furnace observation apparatus has a structure in which the cooling air used for cooling the CCD camera will leak into the furnace, whereby NO.sub.x is likely to be formed in the furnace by the leaked air. Further, it has a drawback that the furnace is cooled by the leaked air. Especially, in the case of a glass melting furnace, if NO.sub.x is formed in the furnace or if the temperature in the furnace changes, such will cause deterioration of the quality of glass, or such is undesirable from the viewpoint of the environmental safety.